Field of the Invention
As world population increases, food production must also increase. In addition to being economically desirable, efficient food production is becoming essential for survival. There are, therefore, continuing efforts to find new agents which improve food production. Drugs which increase feed-utilization efficiency in ruminants are among the new agents being sought.
The mechanism for utilization of the major nutritive portion (carbohydrates) of ruminant feed is well known. Microorganisms in the rumen of the animal ferment carbohydrates to produce monosaccharides and then degrade these monosacchrides to pyruvate compounds. Pyruvates are metabolized by microbiological processes to form acetates, butyrates or propionates, collectively known as volatile fatty acids (VFA). For a more detailed discussion, see Leng in "Physiology of Digestion and Metabolism in the Ruminant," Phillipson et al., Ed., Oriel Press, pp. 408-410.
The relative efficiency of utilization of the VFA's is discussed by McCullough, Feedstuffs, June 19, 1971, page 19; Eskeland et al., J. An. Sci. 33, 282 (1971); and Church et al., "Digestive Physiology and Nutrition of Ruminants," Vol. 2, 1971, pp 622 and 625. Although acetates and butyrates are utilized, propionates are utilized with relatively better efficiency. Furthermore, when too little propionate is available, animals may develop ketosis. A beneficial drug, therefore, encourages animals to produce propionates from carbohydrates, thereby increasing carbohydrate-utilization efficiency and also reducing the incidence of ketosis.